Sealed self-adjusting bearing assembly

ABSTRACT

A self-adjusting bearing assembly comprising a ball member, a connector member, and a bearing seat component having at least two seat members arranged to receive the ball member therebetween. The ball member has a shaped segment providing an outer bearing surface, and the seat members include correspondly shaped inner bearing surfaces for engaging the outer bearing surface of the ball member. A slack removal mechanism is provided to urge a movable one of the seat members toward the ball member and may comprise a pressure chamber having a wall formed by a resilient diaphram positioned adjacent a pressure surface of the movable seat member, and a fitting for pressurizing this chamber with a fluid. The assembly may include a second fitting for feeding lubricant from the pressure chamber to the bearing surfaces. Optionally, a screw member may be provided for exerting an adjustable mechanical force to urge the movable seat member against the ball member.

RELATED APPLICATIONS

This disclosure is an improvement over the self-adjusting bearingassembly described in prior application Ser. No. 08/175,713 which issuedas U.S. Pat. No. 5,435,652, the entire contents of said patent beingexpressly incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to the field of ball joints, and in particular, toa self-adjusting ball joint providing a slack free bearing assembly.

BACKGROUND OF THE INVENTION

Ball joints usually are made up of a ball member and a bearing seatmember. Such joints may also be referred to as universal joints sincethey allow movement around the joint in multiple directions, unlikejoints which allow movement around an axis in only one plane, such ashinges.

The ball member of ball joints has a spherically-shaped bearing surfaceformed over at least a portion of its outer surface. The bearing surfacemay be formed over only a central portion of the ball member and one ormore other portions may have non-spherical surfaces. One side of theball member may be connected to a connector member, such as a connectingarm, rod, stub or other elongated means for attaching the ball member toa frame member, an arm member, or other support member. The connectormember may include a threaded end which facilitates attaching theconnector member to the support member.

The bearing seat member has a bearing surface on its inner surface whichis shaped to complement the bearing surface on the ball member so thatthese bearing surfaces are in sliding engagement with each other. Aportion of the bearing seat member, or a housing in which it is mounted,may be connected to a movable member, such as a tie rod moved by asteering mechanism.

The bearing seat member of a bearing assembly has a passage connectingthe interior socket formed by its bearing surface with the outside ofthe member. When the ball member is engaged in the socket of the seatmember, the connector member attached to the ball member extends throughthis passage and is connected to the support member of whateverapparatus the bearing assembly is being used with. The passage must besufficiently wide to allow the ball member freedom of movement over thedesired range, but not so large as to allow the ball member to fall outof the socket or to allow the seat member to travel over too great arange of movement.

Ball joints and bearing assemblies having a ball member are used in avariety of well known applications. For instance, trailer hitches forautomobiles towing trailers usually include a ball member attached to anarm which is then fixed to the frame of the car, and a bearing seatmember attached to a tongue extending from the trailer being towed. Balljoints are also an integral part of vehicle steering assemblies andsuspension systems. For example, in steering systems, a ball joint inthe form of a rod end bearing may be used to connect a tie rod to thearm of a steering knuckle. In vehicle suspension systems, ball jointsmay be used to connect an independent suspension between the vehicle andthe wheel. Ball joints are also used in a variety of other applications.

While ball joints of the type described above are in use, the bearingsurfaces on the ball member and the bearing seat member rub against eachother. As the two bearing surfaces rub against each other, the bearingsurfaces can be worn down through friction, causing the joint to becomeloose and members of the steering assembly to move from their intendedpositions. Slack therefore develops in the steering assembly and thesteering control becomes sloppy.

As a result, the vehicle will more easily move away from the path theoperator directs it on, the vehicle steering will become less preciseand less predictable, and the vehicle therefore may become difficult tocontrol. For example, 0.002 to 0.003 inch of slack in the ball joint ofa vehicle steering assembly is sufficient to cause the vehicle to turnaway from straight ahead. Obviously, a vehicle having a steeringassembly in which such slack exists may be difficult to control, and mayeven be dangerous. The problems caused by a loose joint can beespecially bad if the vehicle is a large vehicle, such as a truck.

Slack in other ball joints can cause similar problems. For instance,where a ball joint is incorporated into a trailer hitch, a slack jointcan cause the trailer to sway from side to side behind the towingvehicle. Such a situation can be very dangerous both to the persontrying to control the vehicle and other motorists on the road.Similarly, a slack joint in a vehicle suspension system can adverselyeffect the safety of the vehicle, as well as the quality of the ride andthe comfort of the occupants.

As evident from the above discussion, slack in ball joints can haveserious consequences to the apparatuses in which the ball joints areincorporated, and to the users thereof. Another problem with prior balljoints is that they may be excessively tight when initially installed inan effort to lengthen their usable life before excessive slack occurs.Tight ball joints are difficult to articulate because of high frictionbetween the ball and seat members, which may interfere with properfunctioning of the associated equipment. There is therefore a need for aslack free ball joint assembly with low friction between the ball andseat members throughout its useful life.

Several constructions of a slack free ball joint assembly are describedin the inventor's prior U.S. Pat. No. 5,435,652 referred to above.However, these constructions have the disadvantage of allowing highpressure lubricant to leak around the movable bearing seat and ambientpressure lubricant to leak around the connector member. In addition, insome applications, higher lubricant pressures than desirable are neededto stabilize the movable bearing seat against movement in the directionof forces applied along the axis of the tie rod. High lubricantpressures are not desirable because they may make the ball jointexcessively tight.

SUMMARY OF THE INVENTION

A principal object of the present invention is to overcome the foregoingproblems of the prior art by providing a ball joint assembly whichincludes a mechanism for taking up slack in the ball joint as itdevelops, and which is never excessively tight because its structureinherently opposes forces applied along the tie rod axis. A furtherobject is to provide such a ball joint mechanism which may be set andcalibrated once, and then over time will remain true to those settingsrather than becoming loose. Another object of the invention is toprovide such a ball joint mechanism wherein the pressurized lubricantchamber is tightly sealed relative to the movable bearing seat.

The present invention thus provides an improved design for a ball jointbearing assembly. This ball joint assembly may serve as a self-adjustingtie rod end bearing between a tie rod and the arm of a steering knuckle.In this rod end bearing, the spherical head or ball member of theassembly is captured between at least two seat members each preferablymade of a low friction plastic material and having inner surfacesconfigured complementarily to the ball member.

The two seat members are contained within a cylindrical cavity in ahousing formed by an enlarged end portion of the tie rod. The axis ofthis cavity is transverse to the tie rod axis and extends generally inthe direction of the connector member attached to a side portion of theball member. The connector member extends away from an opening at oneend of the cavity and an opening at the opposite end of the cavity isclosed by a cap which cooperates with a movable one of the seat membersto form a pressure chamber on the side thereof opposite to the ballmember. This closure cap also holds the ball member and both seatmembers in the tie rod end cavity.

An internal passageway formed through the movable seat member connectsthe pressure chamber with the interface between the ball member of therod end bearing and the seat members. An internal grease fitting issecured in the passageway and has a spring loaded check valve whichprevents unrestricted flow of the grease out of the pressure chamber sothat grease in the chamber may be pressurized. The ball member is heldbetween the movable seat member and a fixed seat member, and the movableseat member is movable in response to chamber pressure to maintain aslack preventing force on these components.

An external passageway through the closure cap connects the pressurechamber with the outside environment. An external grease fitting issecured within this passageway and contains a spring loaded check valvefor admitting grease to pressurize the chamber. A sealing diaphrambetween the pressure chamber and the movable seat member is held inplace by the closure cap and prevents grease in the pressure chamberfrom flowing around the edges of the movable seat member.

The ball member may have an outer bearing surface formed over only aportion of its outer surface, and the seat members may have innerbearing surfaces of corresponding shape and size to ensure that the ballmember rides on an opposing bearing surface at all times. This in turnensures a wide range of movement for such components as may be attachedto the seat member housing. Additionally, precisely machined bearingsurfaces do not have to be formed over as large a surface area of theball and seat members, and the weight of the bearing assembly may bereduced.

In operation, the pressure chamber is filled with a sufficient amount ofgrease or other lubricant fluid to create a substantial pressure againstthe movable seat member, thereby forcing it against the ball member ofthe rod end bearing. Only a relatively low pressure is required becausethis pressure urges the movable seat member in a direction perpendicularto the direction of the steering forces that are supplied along the axisof the elongated tie rod component. This pressure not only holds theball member in place against the fixed seat member, but also takes upany slack as the ball and seat members wear against each other.

Thus, the pressure of grease within the pressure chamber will eliminateany slack that might otherwise develop between the steering knuckle andthe tie rod, while causing only a low level of friction between the balland seat members. The low level of friction allows easy articulatedmovement between the tie rod and steering knuckle. The design of thecheck valve in the internal grease fitting is such that a relatively lowchamber pressure will exceed the spring force of this valve, causinggrease to be released into the interface between the seat members andthe ball member of the rod end bearing.

In another embodiment of the invention, the external grease fitting isprovided with a screw mechanism by which an initial level of force maybe applied to the movable seat member independently of any pressurewithin the pressure chamber. This mechanism constitutes an"adjustingscrew" for mechanically setting a level of friction between the ball andseat members as the starting level when the ball joint is firstinstalled for use. One advantage of the adjusting screw is that theproper low level of friction may be set initially without having to relyon the machining of close tolerances between the ball and seat members.In other words, preloading with the adjusting screw allows a wider rangeof component tolerances such that the cost of manufacturing the ball andseat members may be substantially reduced, thereby making the entireball joint more economical.

Another feature of the adjusting screw is that it may be used either inplace of or as a supplement to the adjusting force provided by fluidpressure in a pressure chamber. Thus, the adjusting screw provides ameans for manually biasing the movable seat member against the ballmember as an alternative to using fluid pressure in a pressure chamber.For example, fluid pressure in the pressure chamber disclosed could belost due to a stuck condition of the internal grease fitting. In thisregard, the pressure chamber may be considered as an automatic means ofadjusting the movable seat member, whereas the adjusting screw may beconsidered as a manual means of adjusting the moveable seat member.

In either case, whether provided automatically or manually, the pressureapplied to adjust the level of force pressing the movable seat memberagainst the ball member is selected to provide just enough force to keepthe ball joint slack free. This level of force will provide sufficientlylow friction between the ball and seat members that the ball joint willallow relatively free and easy articulated movement between twoequipment components connected by the ball joint. These slack free andlow friction characteristics are maintainable throughout the life of theball joint, whether using the automatic adjusting means, the manualadjusting means, or both of these means.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be further understood from the following detaileddescription thereof taken in conjunction with the accompanying drawings,in which:

FIG. 1 is an elevational side view in partial cross section of aself-adjusting bearing assembly according to one embodiment of thepresent invention;

FIGS. 2 is an overhead view of the embodiment shown in FIG. 1incorporated into a vehicle steering assembly;

FIG. 3 is a fragmentary sectional view showing structural details of theFIG. 1 embodiment when the movable seat member is in an initialposition;

FIG. 4 is a fragmentary sectional view showing structural details of theFIG. 1 embodiment when the movable seat member is in an intermediateposition;

FIG. 5 is a fragmentary sectional view showing structural details ofFIG. 1 embodiment when the movable seat member is in a terminalposition;

FIG. 6 is an end view of the inner face of a movable seat member whichhas been modified to include a spiral lubricant channel;

FIG. 7 is an elevational side view in partial cross-section of aself-adjusting bearing assembly according to another embodiment of thepresent invention; and

FIG. 8 is an elevational side view in partial cross-section showing theself-adjusting bearing assembly of FIG. 7 wherein the movable seatmember has moved inward toward the ball member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a preferred embodiment of a self-adjusting rod end bearingassembly 8 according to the present invention. This embodiment may beincorporated into a vehicle steering assembly as shown in FIG. 2, and isonly one example of a self-adjusting bearing assembly which may be madein accordance with the teachings of the present invention. Theembodiments may vary, depending upon the application. Thus, variationsof the bearing assembly and of its ball joint may be incorporated into avariety of devices. Furthermore, each of the components of the bearingassembly may be made up of one or more elements, and the invention mayalso include various other components.

The self-adjusting rod end bearing assembly 8, according to theembodiment shown in FIG. 1, includes a bearing housing 11, and an endclosure cap 12 forming a pressure chamber 14. The rod end bearingassembly also comprises a ball member 5 and a connector member or pin 6.The ball member 5 includes a spherically-shaped bearing surface 7. Thebearing surface 7 may cover the entire ball member 5 with the exceptionof the connector member 6. Alternatively, the bearing surface 7 may beformed on only a mid-section of the ball member as in the embodimentshown in FIG. 1.

The bearing surface 7 may also have a non-spherical shape. For example,the ball member may be replaced by a head member having an ellipticalcross-section. Either the major axis or the minor axis of the ellipticalcross-section may be positioned parallel to the longitudinal axis of theconnector member to allow the head member to rotate about the parallelaxis. However, the head member would resist movement about other axes.

In the embodiment shown in FIG. 1, two portions of the ball member donot have a bearing surface formed on them. One of these has asubstantially flat end surface 16 indented from where the surface of acomplete sphere conforming to the bearing surface 7 would otherwise belocated. End surface 16 cooperates with a pair of bearing seat members 9and 10 to form an ambient pressure lubricant chamber 17. The otherportion of the ball member not having a bearing surface is the proximalportion 16' connected to the connector member 6.

The connector member 6 of the rod end bearing assembly 8 is a generallyelongated member or pin extending outward from the ball member 5. In theembodiment shown in FIG. 1, the length of the connector member 6 isabout one to two times the diameter of the ball member. However, theconnector member is not limited to that length and therefore it may belonger or shorter, depending upon the application. The connector membermay also have other shapes.

The connector member 6 preferably includes connection means. Theconnection means on the connector member 6 is a tapered portion 15 and athreaded portion 18 formed on its distal end as shown in FIG. 1. Theconnection means is used to connect the rod end bearing to a lever armor other articulated member of the apparatus on which the bearingassembly is being used. The lever arm contains a tapered aperture forreceiving the tapered connector portion 15 and these two taperedelements are firmly jammed together by tightening a nut onto thethreaded portion 18. Other types of connection means may be used toattach the rod end bearing to the articulated member of an apparatus.

The ball member and connector member may be formed from the same pieceof metal or may be formed separately and then joined together. The ballmember and the connector member may be cast separately in differentmolds and then joined together by welding or the like, or they may becast as one piece. Alternatively, the ball and the connector may beforged separately or together. Other materials, such as plastic, andother techniques may also be used to form the ball member and theconnector member.

The self-adjusting bearing assembly also comprises the bearing seatmeans provided by the at least two bearing seat members 9 and 10. Eachbearing seat member may be made up of one or more pieces. In theembodiment shown in FIG. 1, the bearing seat means includes the twobearing seat members 9 and 10. Each of these bearing seat members ismade up of one piece. The bearing seat members preferably are made oflow friction plastic, but may be made of metal or any other suitablebearing material.

The bearing seat members 9 and 10 are housed within a cylindricalchamber 19 of housing means 11. Preferably, the entire outer perimeterof at least some portion of each bearing seat member directly contactsthe interior surface of cylindrical wall defining chamber 19. At leastone bearing seat member must be movable. The other bearing seat membermay be fixed or movable. In the embodiment shown in FIG. 1, bearing seatmember 9 is movable and bearing seat member 10 is fixed.

The bearing seat members 9 and 10 have bearing surfaces formed on thesurface of each which faces the ball member 5 and engages its bearingsurface 7. The seat member bearing surfaces preferably arecomplementarily shaped to the bearing surface of the ball member.Therefore, as with the bearing surface on the ball member, the bearingsurface on each seat member preferably is spherically-shaped.

The bearing seat members preferably extend around a majority of thesurface of the ball member. However, the bearing seat member 10 stopsshort of the area of the ball attached to the connector member. Thebearing seat member 9 has a counterbore forming a gap or chamber 17adjacent to the flat area 16 of the ball member on its side opposite theconnector member 6. At least a portion of the bearing surface of eachbearing seat member contacts and rides on the bearing surface 7 of theball member at all times. However, these contacting surfaces may beseparated from each other by a thin layer of a lubricating substance.

A compression slot 13 exists between the inner opposing surfaces of thetwo bearing seat members 9 and 10 when the bearing assembly isassembled. The compression slot 13 allows the movable bearing seat 9 toadjust its position relative to the fixed bearing seat 10 and the ballmember 5 in response to pressure in the pressure chamber 14 as thebearing surfaces wear. The initial width of compression slot 13 definesthe maximum amount of axial movement of seat 9 relative to seat 10 asthe bearing surfaces wear. Although not shown here, the seats 9 and 10may optionally include abutting guide surfaces as described in U.S. Pat.No. 5,435,652 to help maintain the bearing seat members in properalignment when seat member 9 moves as the bearing surfaces wear.

The housing means 11 in the embodiment shown in FIG. 1 is a single,elongated, hollow cylindrical body which is open at both ends and isformed at each end of a tie rod 50. Although only the right end is shownin FIG. 3, the bearing assembly of the invention is also used at theleft end (not shown) of tie rod 50, this left end bearing assembly beinga mirror image of that shown in FIG. 1. The housing means 11, theclosure cap 12, the seat members 9 and 10 and the chambers 14 and 19 mayhave other cross-sectional shapes, as long as the space within thehousing means and closure cap can accommodate the seat members, the ballmember, and the pressure chamber. Also, the housing means 11 maycomprise a plurality of housing members joined together to form a singlehousing structure.

The housing 11 has a first opening 37 formed through an end wall 60, andthrough which the connector member 6 extends. Preferably, the width ofopening 37 is at least as large as the opening 49 in the outer face ofthe bearing seat member 10. The openings 37 and 49 may be circular,square or any other suitable shape. The opening 37 in housing wall 60preferably has an outwardly beveled surface facing the connector member6. The beveled surface, as shown in the embodiment of FIG. 1, ispreferably angled away from the connector member so that the opening 37becomes wider as the distance away from the ball member increases. Thebeveled surface allows the connector member to pivot through an arcaround the center of ball 5 by providing space for the connector memberto move laterally as illustrated by fragmented lines 15' and 15". Thebeveled surface may also act as a stop surface to limit the arc throughwhich connector member 6 may pivot relative to housing means 11.

Preferably, the area between the side of the opening 37 and theconnector member 6 is sealed by a boot seal 38. The boot seal 38preferably is made of an elastomeric material which will flex as theconnector member 6 pivots to follow corresponding rotation of ballmember 5 within chamber 19. The boot seal contacts or is attached to aridge 63 of the housing means 11 and to a beveled side surface 6' of theconnector member 6. The boot seal 38 helps to contain any lubricantwhich seeps out from between the ball member 5 and the opening 49 ofbearing seat member 10, and also to prevent dirt and other debris fromentering the bearing assembly.

The pressure chamber 14 is provided on housing means 11 by the closurecap 12, which is secured to a corresponding end portion of a cylindricalhousing sidewall 21 by a crimped sidewall projection 20 of housing 11.Clamped between the rim 22 of cap 12 and the sidewall end is a diaphram23 made of a resilient material, such as synthetic rubber. Diaphram 23completely covers a second opening 39 in housing 11 at its end oppositeto end wall 60. Diaphram 23 includes an inwardly projecting rib 24around its outer periphery and this rib is tightly clamped by the caprim 22 in sealing engagement within a correspondingly shaped groove 25in the sidewall end to form a tight fluid seal. The cap 12 thus providesa second chamber contiguous to, but of different shape and of smallersize than, the cylindrical chamber 19, which is here designated as thefirst chamber. Although the diaphram and its rib are preferablycircular, they may have other shapes, such as square or rectangular.

An elevated pressure is created within pressure chamber 14 byintroducing a fluid substance, such as grease, into the pressure chamberthrough an external valve fitting 40 in a passage 39 through cap 12, asdescribed in more detail below. The size and shape of cap 12 determinesthe size of the pressure chamber 14, which consequently determines theamount of fluid required to be introduced into the pressure chamber tocreate the desired pressure.

The movable bearing seat member 9 substantially abuts the closure cap 12initially, i.e., before substantial wear has occurred as shown in FIG.3. The elevated pressure created within the pressure chamber 14 by thepressurized fluid presses the diaphram 23 against the outer "pressure"surface 29 of the movable seat member 9, and thereby forces the movableseat member 9 toward the ball member 5. FIGS. 3, 4 and 5 illustrate themovement of seat member 9 and diaphram 23 as the seat members becomeworn by their engagement with the ball member.

To facilitate lubrication of the interface between the bearing surfaceson the ball member and the bearing seat members, the bearing seatmembers 9 and 10 may include lubrication access grooves 70 and 71,respectively. Each lubrication access groove, if included on the bearingseat members, is a narrow, shallow indentation which may extend radiallyand axially along the bearing surface of each seat member as shown inFIG. 1. The access grooves on opposing seat members 9 and 10, togetherwith slot 13, form a substantially continuous passageway at leastpartially around the ball member.

The peripheral extent of the continuous passageway is defined by a firstend wall 73 on the seat member 10, and by a second end wall (not shown)on the seat member 10 at the opposite end of the passageway, whichmirrors the grooves 70, 71. The groove end walls minimize the amount oflubricant that may leak out from the access grooves 70 and 71 into thefree space around the connector member 6. Instead of extending axiallyas in FIG. 1, the lubricant grooves may extend transversely at an acuteangle to form a spiral as illustrated by grooves 70' and 70" in FIG. 6.

The grooves 70, 71 and the ball/seat interface are supplied with thelubricating fluid substance (lubricant) via an outlet passage 26 formedin the movable bearing seat member 9. Passage 26 connects lubricantchamber 17 between the ball member 5 and the bearing seat member 9 withthe pressure chamber 14, in which a supply of lubricant is kept underpressure by external valve fitting 40. Passage 26 contains an internalvalve fitting 27, which contains a spring loaded valve for releasinglubricant to chamber 17 as described below.

In the embodiment shown in FIG. 1, bearing seat member 10 is fixedwithin housing means 11 and bearing seat member 9 is movable upward inresponse to lubricant pressure in the pressure chamber 14. The movablebearing seat member is adjacent to the pressure chamber 14, and is thelower bearing seat member 9 in the embodiment shown in FIG. 1. Thediaphram 23 is firmly secured to the outer end of seat member 9 by aplate 75 having a boss 76 which is threaded to the body of valve fitting27. The diaphram is preferable anchored against lateral movement by apair of circular concentric ribs 78, 79 which fit within correspondinglyshaped concentric grooves in the outer face of seat member 9. Thediaphram also may be attached to the outer seat face by an adhesive.

The outer periphery of diaphram 23 sealingly engages the end surface ofthe housing wall 21 which defines the cylindrical chamber 19 in housingmeans 11. The diaphram 23 thus prevents pressurized lubricant containedin pressure chamber 14 from leaking around the exterior of bearing seatmembers 9 and 10 and into the opening 37 adjacent to connector member 6.This insures that the pressure on the lubricant in pressure chamber 14is positively maintained. Although in the embodiment shown in FIG. 1,only the bearing seat member 9 is movable and has a sealing diaphram,each bearing seat member may be movable by a corresponding pressurechamber and may have a corresponding sealing diaphram.

The movable bearing seat member 9 also includes a second counterbore 31at the inner end of the outlet passage 26 for receiving a flange 32 atthe inner end of the internal check valve fitting 27. A central passage28 of the fitting 27 provides fluid communication between the pressurechamber 14 and the surface of the ball member for the purpose ofintroducing some of the lubricant contained in the pressure chamber intothe interface between the ball member 5 and the bearing seat members 9and 10.

Internal fitting 27 and its passage 28 provide means for relievingexcess pressure within pressure chamber 14, while simultaneouslyintroducing the lubricating substance around the ball member 5, asdescribed in more detail below. The internal fitting 27 may includeconnecting means other than the threaded connection between it and plate75 for retaining the internal fitting in the passage 26. For example,the internal fitting may be swaged to the boss 76, or held in theaperture of the boss by frictional engagement or welding.

The internal fitting 27 includes upset portions which may be formed byswaging and provide inwardly projecting inner and outer lips at therespective ends of central passage 28 so that a spring 33 and a ballvalve 34 are held in place within the central passage. After the springand ball valve are inserted in passage 28, the inner end of the spring33 is retained by the corresponding inner lip. At the other end of thepassage, the spring applies pressure to the ball valve 34, forcing theball valve 34 to close a smaller inlet passage 35 defined by the outerlip which serves as a seat for the ball valve.

Fitting 27 serves as a check valve because flow from passage 28 intochamber 14 is prevented when ball valve 34 is held in its seatedposition by spring 33. Lubricating fluid will only flow through theinternal fitting if the pressure within pressure chamber 14 issufficiently great to overcome the spring force of the spring 33 in theinternal fitting 27. The pressure required to open ball valve 34 may bechanged by changing the spring within the internal fitting.

Preferably, the fluid introduced into the pressure chamber 14 is aviscous liquid. More preferably, the fluid is a lubricating liquid, suchas grease. By using grease as the pressure generating fluid, this fluidserves a second purpose, namely, the grease lubricates the respectivebearing surfaces by passing through the internal fitting 27, the chamber17 and the grooves 70 and 71, and into the interfacial area between theball member 5 and the bearing seat members 9 and 10.

The grease is introduced into pressure chamber 14 through the externalpassage 39 containing the external fitting 40. The external passage 39is formed in the wall of closure cap 12 and the external fitting 40 ispreferably threaded therein. The external passage 39 and externalfitting 40 preferably are similar to the internal passage 26 and theinternal fitting 27 in the movable bearing seat 9.

The external fitting 40 has an internal passage 43 formed through itsentire length. The passage 43 preferably includes a central portion ofsufficient diameter to contain a spring 45 and a ball valve 46. Smallerdiameter upset portions are formed, such as by swaging, at each end ofthe passage 43 to retain spring 45 and ball valve 46 therein. The ball46 is forced outward against a valve seat formed by an outer lip 48 onthe outer end of fitting 40 by the spring 45, and also by thepressurized fluid within the pressure chamber 14. Thus, the externalfitting 40 is a one-way check valve which allows lubricant to beintroduced into the pressure chamber but prevents the lubricant fromleaving the chamber. Internal fitting 27 therefore provides the onlyoutlet for grease in pressure chamber 14.

The external fitting 40 may also be secured in the external passage 39by suitable means other than the threaded connection shown in FIG. 1,such as by welding, swaging or the like. The portion of external fitting40 which extends away from the surface of cap 12 may include means, suchas annular groove 47, for attaching a source of the lubricant to be usedin the pressure chamber 14, such as a grease gun (not shown). Theattachment means is used to facilitate the introduction of lubricantunder pressure into the pressure chamber.

Fluid is introduced into the pressure chamber 14 until the pressure issufficient to hold the bearing seat members 9 and 10 securely againstthe ball 5 while all steering forces necessary for precisely steeringvehicle wheel 52 are being transmitted between tie rod 50 and steeringknuckle 61. When the fluid pressure exceeds the force of spring 33 onball 34 in the internal fitting 27, the fluid will be forced around ball34, through fitting passage 28, chamber 17 and access grooves 70 and 71,and into the interface between the ball member and the bearing seatmembers. The pressurized fluid is prevented from flowing between thebearing seat member 9 and the housing wall 21 by the sealing diaphram23. This sealing member positively prevents the fluid from travelingaround bearing seat member 9 as this seat member moves due to wear onthe bearing surfaces.

The embodiment of the bearing assembly shown in FIG. 1 is assembled byfirst inserting the fixed bearing seat member 10 into the housingchamber 19 until it abuts the end wall 60 of this cavity. Next, the ballmember 5 is inserted through the opening 39 while passing the connectorpin 6 through the opening 49 in seat member 10 and the opening 37 in theend wall 60 of the housing means 11. Then, the movable bearing seatmember 9, with the fitting 27 inserted therein, is positioned into thehousing chamber 19 until it firmly abuts the ball member 5.Subsequently, the hole in the center of diaphram 23 is passed over theoutwardly projecting threaded end of fitting 27, and the boss 76 ofplate 75 is threaded and tightened down onto this threaded end to securediaphram 23 against the outer face of seat member 9. This also firmlyseats flange 32 in counterbore 31.

Alternatively, diaphram 23 and fitting 27 may be secured (locked) inposition by plate 75 before the movable bearing seat 9 is inserted intohousing chamber 19. Thereafter, cap 12 is placed over diaphram 23 andfitting 27 and is clamped in position by swaging or otherwise deformingthe end of sidewall 11 to form the crimped sidewall projection or ridge20. Although ridge 20 is preferably crimped around its entire periphery,it may instead be crimped only at regularly spaced segments.

Fixing the closure cap 12 to the abutting end of housing sidewall 21locks the bearing seat members 9 and 10 and the ball 5 of the rod endbearing 8 securely within the housing means 11. The boot sealing member38 may then be placed about the connector member 6 and secured to thecircular ridge 63 adjacent to the end wall 60 of the housing means 11.Thereafter, the pin 6 is fastened to the steering knuckle 61 bytightening the nut 56 on the pin threads 18. Pressure chamber 14 is thenpressurized with lubricant to a sufficiently high pressure so that thepressure applied to the ball member 5 by the two bearing seat members 9and 10 is sufficient to prevent any significant slack between the ballmember and the bearing seat members, but not so great that the ballmember will not move freely with a lubricant between the bearingsurfaces.

Grease is introduced into the pressure chamber 14 through externalfitting 40 until the pressure is sufficient to open the check valve infitting 27. Grease then flows through passage 28 and grooves 70 and 71,and spreads out over the bearing surface 7 of the ball 5 and thecorresponding bearing surfaces of bearing seat members 9 and 10. Asthese bearing surfaces wear, movable seat member 9 moves toward chamberend wall 60 to maintain the slack free engagement between the bearingsurfaces of the seat members and the opposing bearing surface of ball 5.This is illustrated by the progressive movement of seat member 9 anddiaphram 23 shown in FIGS. 3-5.

FIG. 2 shows the bearing assembly of the present invention being used inthe steering assembly of a land vehicle, such as a truck or automobile.The self-adjusting rod end bearing 8 connects the tie rod 50 of thesteering system to the arm 51 of the steering knuckle 61. Othercomponents of the steering and suspension system shown in FIG. 2 includethe vehicle wheel 52, a king pin 53, leaf springs 54, and axle 55. Theconnector pin 6 of the rod end bearing assembly 8 is secured to the arm51 by the nut 56, which pulls the tapered surface 15 of the pin intotight engagement with a corresponding tapered surface (not shown) of anaperture through the end portion of arm 51.

Another embodiment of the invention is shown in FIGS. 7 and 8 whereinthe fixed external fitting 40 of FIG. 1 has been replaced with anadjustable external screw fitting 40'. The adjustable screw fitting 40'is threaded within an opening 39' through end cap 12', and the treads onthe fitting 40' are arranged relative to the threads in the opening 39'such that the fitting is axially adjustable for inward and outwardmovement relative to the boss 76' on the plate 75'. After adjustment,the axial position of the fitting 40' is preferably locked in place by alocking nut 80. The fitting 40' includes an internal chamber 82 definedby a surrounding wall 84 such that the inner end 85 of the fitting 40'will not interfere with operation and/or axial adjustment of theinternal valve fitting 27' when the inner end 85 butts against the boss76' as shown in FIG. 7. The remaining features of the internal valvefitting 27' and the external valve fitting 40' are essentially the sameas those of the internal valve fitting 27 and the external valve fitting40 of FIG. 1.

The introduction of a fluid pressure into the pressure chamber 14' ofthe FIG. 7 embodiment causes the same slack removal pressure on themovable seat member 9' as does the introduction of a pressurized fluidinto the pressure chamber 14 of the FIG. 1 embodiment already described.However, in the FIG. 7 embodiment, the valve fitting 40' constitutes anadjustable screw means for preloading the movable seat member 9' with aslack removal force independent of the fluid pressure in the pressurechamber 14'.

Although this preloading force may be less than, equal to, or greaterthan the slack removal force provided by fluid pressure in chamber 14',it is preferable that the preloading force provided by the adjustablescrew means be approximately equal to the slack removal force providedby fluid pressure. If these relative forces are substantially equal, theslack removal force will remain substantially constant as the boss 76'moves away from the outer end 85 of the screw means due to wear of thebearing seat members as illustrated in FIG. 8.

The slack removal forces provided by both the screw means and the fluidpressure means are preferably of a sufficiently low order of magnitudethat the engagement between the seat and ball members is neverexcessively tight, thereby providing both a low friction and a slackfree ball joint. One way in which to establish this desired level ofpreloading with the screw means is to firmly tighten the inner end 85 ofthe fitting 40' against the boss 76', and then to back off the fitting40' by a slight amount, such as a quarter or a half turn, beforetightening the lock nut 80 to lock the fitting 40' in the resulting lowfriction position. The ease of articulated movement between componentsconnected by the ball joint may then be determined and chamber 14'pressurized to a pressure providing substantially the same ease ofarticulated movement.

Use of the adjustable screw fitting 40' provides several importantadvantages. These include allowing a wider range of tolerances in thefit between the bearing surfaces of the seat members and the bearingsurface of the ball member. The use of screw fitting 40' also permitsapplying a slack free force on moveable seat member 9' in case a loss ofpressure occurs in the chamber 14', such as might be caused by amalfunction of the ball valve 34'. For example, if ball valve 34'becomes stuck in an open position such that the fluid pressure inchamber 14' is lost, locking nut 80 may be loosened and fitting 40'screwed in manually further than shown in FIG. 8, until its inner end 85again butts against boss 76' and mechanically applies a slack removalforce to moveable seat member 9'. Such manual adjustments may berepeated periodically as the ball and seat members wear so that anappropriate level of slack removal force is maintained throughout thelife of the unit even in the absence of pressure within chamber 14'.

It is therefore an important feature of the embodiments of both FIGS. 1and 7 that the level of slack removal force applied to the movable seatmember may be just enough to keep the ball joint slack free, while atthe same time providing a low friction joint that permits easyarticulated movement of the equipment components connected by the balljoint. These same low friction and slack free characteristics aremaintainable throughout the life of the joint, either by usingpressurized fluid in the corresponding pressure chamber, or by manualadjustment of the adjustable screw fitting of the embodiment of FIG. 7.

There are several additional features of the invention shown in FIGS. 7and 8 that are not shown in FIG. 1, although they may be used with theFIG. 1 embodiment. These include the O-ring seal 86 between the housingwall 21 and the seat member 9', the O-ring seal 88 between the internalvalve fitting 27' and the seat member 9', and the O-ring seal 90 betweenthe fitting 40' and the end cap 12'. In addition, a pair of circularconcentric ribs 92 and 94 are provided on the diaphram 23', and theseribs fit within correspondingly shaped concentric grooves in the innerface of plate 75' to anchor the diaphram against lateral movementrelative to the plate 75'. Similar to the diaphram 23 of FIG. 1, a pairof circular concentric ribs 78' and 79' are provided to anchor thediaphram against lateral movement relative to the outer pressure surface29' of the movable seat member 9'.

The specific constructions shown and described for the external andinternal fittings in the embodiments disclosed are for the use of aliquid as the fluid for pressurizing pressure chambers 14 and 14'.However, with appropriate modifications easily recognized by thoseskilled in the art, the internal and external fittings may be adaptedfor the use of a gas as the pressurizing fluid in pressure chambers 14and 14'. In this alternative embodiment, a separate fitting may beprovided to introduce a lubricating fluid into the gap 13 between thebearing seats as shown and described in U.S. Pat. No. 5,435,652.

The self-adjusting bearing assembly of the present invention may be usedanywhere that known non-self-adjusting bearing assemblies are currentlybeing used. Thus, self-adjusting bearings may be used in a number ofother applications, such as the interconnected and articulated armsegments used in robotic assemblies of the types now widely employed inmanufacturing assembly lines. In this application, a self-adjustingbearing assembly may be placed at each end of each segment of therobot's articulated arm(s).

The self-adjusting bearing assembly also may be used as a trailer hitch.In this application, the ball 5 and connector pin 6 of rod end bearingassembly 8 would be attached to the rear of the vehicle frame, as isnormally the case with trailer hitches. The bearing seat portion of theassembly within its housing means 11 would be at the distal end portionof a tongue extending from the trailer.

In use, as a bearing assembly wears, the friction between the ballmember and the bearing seat members will wear away some of the materialat the bearing surfaces of these members, preferably on the seatmembers. As the bearing surfaces wear, the pivotal joint provided byconventional bearing assemblies can become sloppy because space or gapsdevelop between opposing bearing surfaces. However, with the presentinvention, such space or gaps cannot develop between the bearing surfaceof the ball member and bearing surfaces of the bearing seat membersbecause, as the bearing surfaces wear, the pressure of lubricant in thepressure chamber 14 or 14', or the manually adjusted screw fitting 40',will continuously force the movable bearing seat 9 or 9' against theball member 5 and the ball member 5 against the stationary bearing seat10.

The bearing assembly of the present invention will need to be replacedmuch less frequently than conventional bearing assemblies becausesubstantially greater amounts of wear can occur in the former relativeto the latter without resulting in a slack connection. Thus, with abearing assembly incorporating the present invention, replacement ofworn bearing parts can be delayed for a much longer period of time. Theonly maintenance which will routinely be required on the presentinvention is the addition of lubricant to maintain adequate pressure inthe pressure chamber. The bearing components will only need to bereplaced if they become severely worn, and it is believed that this maynot occur during the useful life of many vehicles. However, if needed,replacement is easily accomplished by reversing the assembly proceduredescribed above, followed by reassembly with new parts.

What is claimed is:
 1. A self-adjusting bearing assembly,comprising:bearing means comprising a ball member and a connectormember, said ball member having an outer bearing surface extending aboutat least a central portion of the ball member; housing means defining abearing chamber having an open end; bearing seat means comprising atleast two opposing bearing seat members arranged in said bearing chamberto define therebetween a space for receiving said ball member, each ofsaid bearing seat members having an inner bearing surface conformingsubstantially to the shape of the outer bearing surface of said ballmember and arranged to engage the outer bearing surface of said ballmember while allowing said ball member to rotate, at least one of saidbearing seat members being movable in said bearing seat chamber, andsaid connector member extending through a passage formed at least inpart by said housing means; and adjusting means for urging said movablebearing seat member toward said ball member such that the inner bearingsurfaces of said seat members engage the outer bearing surface of saidball member, said adjusting means comprising a resilient diaphramarranged to cover and seal the open end of said bearing chamber, apressure chamber in fluid communication with a first surface of saiddiaphram, and means for pressurizing said pressure chamber with a fluid,a second surface of said diaphram opposite to said first surface beingarranged to apply pressure to a pressure surface of said movable bearingseat member in response to said chamber pressure, said pressure surfacebeing on a side of said movable bearing seat member opposite from saidball member, and said movable bearing seat member being arranged to beforced against said ball member by said diaphram when said pressurechamber is pressurized by said fluid.
 2. A self-adjusting bearingassembly according to claim 1, wherein said housing means comprises ahousing member forming said bearing chamber, and wherein said pressurechamber is provided by cap means arranged on said housing member toclose said bearing chamber.
 3. A self-adjusting bearing assemblyaccording to claim 2, wherein a peripheral portion of said closure capis secured to an end portion of said housing member, and wherein a ribextending around a peripheral portion of said diaphram is held insealing engagement with a groove in said housing end portion by saidclosure cap peripheral portion.
 4. A self-adjusting bearing assemblyaccording to claim 1, wherein said pressurizing means comprises an inletpassage in fluid communication with the pressure chamber, and valvemeans in said inlet passage for permitting said fluid to be introducedinto said pressure chamber and for preventing said introduced fluid fromescaping from said pressure chamber through said inlet passage.
 5. Aself-adjusting bearing assembly according to claim 4 further comprisingfitting means for introducing said fluid from said pressure chamber intoan interface between the bearing surface of said ball member and thebearing surfaces of said seat members.
 6. A self-adjusting bearingassembly according to claim 1, wherein said movable bearing seat membercomprises fitting means for permitting said fluid to be introduced fromsaid pressure chamber through said movable bearing seat member into aninterface between the inner bearing surface of said movable bearing seatmember and the outer bearing surface of said ball member when said fluidpressure in said pressure chamber is greater than a predetermined value.7. A self-adjusting bearing assembly according to claim 6, wherein saidfluid is a lubricating substance and a groove is formed in a portion ofthe inner bearing surface of said movable bearing seat member, whereinsaid fitting means is received in a passage formed in said movablebearing seat member, wherein the groove in said movable member bearingsurface is in fluid communication with said movable member passage, andwherein said groove provides a channel for distributing said lubricatingsubstance between said outer bearing surface of the ball member and saidinner bearing surfaces of the bearing seat members.
 8. A self-adjustingbearing assembly according to claim 7, wherein said movable bearing seatmember is arranged to move in a direction of an axis of said bearingchamber, and wherein said lubricating groove forms a spiral shapeextending around said axis.
 9. A self-adjusting bearing assemblyaccording to claim 1, wherein the other of said bearing seat members isfixed in position within said housing means, and said movable bearingseat member is slidable within the bearing chamber of said housing meansin a movement direction; wherein the inner bearing surface of saidmovable bearing seat member is adjacent said ball member on a side ofsaid ball member substantially opposite the inner bearing surface ofsaid fixed bearing seat member; and wherein said movable and fixedbearing seat members are separated by a slot, said slot extendingtransversely to said movement direction to provide a space between saidbearing seat members to allow said movable bearing seat member to movetoward said fixed bearing seat member in response to the pressure offluid in said pressure chamber and the wearing of said bearing surfaces.10. A self-adjusting bearing assembly according to claim 1, wherein saidhousing means is provided by an end portion of an elongated component,wherein said connector member extends through an opening formed in asidewall of said elongated component, wherein said movable bearing seatmember is arranged to move in a direction of an axis of said bearingchamber, and wherein said bearing chamber axis is substantiallyperpendicular to a longitudinal axis of said elongated component.
 11. Aself-adjusting bearing assembly according to claim 1, wherein saidadjusting means further comprises cap means arranged to close the openend of said bearing chamber, and screw means having threads for engaginga threaded opening in said cap means and an inner end arranged to exerta force on the pressure surface of said movable bearing seat member inresponse to rotation of said screw means while in said threadedengagement with said cap means, said force causing said movable bearingseat member to be forced against said ball member and the amount of saidforce being adjustable by said rotation of the screw means.
 12. Aself-adjusting bearing assembly according to claim 1 further comprisingvalve means for preventing fluid pressure in said pressure chamber fromexceeding a predetermined value.
 13. A self-adjusting bearing assembly,comprising:bearing means comprising a ball member and a connectormember, said ball member having an outer bearing surface extending aboutat least a central portion of the ball member; housing means defining abearing chamber having an open end; bearing seat means comprising atleast two opposing bearing seat members arranged in said bearing chamberto define therebetween a space for receiving said ball member, each ofsaid bearing seat members having an inner bearing surface conformingsubstantially to the shape of the outer bearing surface of said ballmember and arranged to engage the outer bearing surface of said ballmember while allowing said ball member to rotate, at least one of saidbearing seat members being movable in said bearing seat chamber, andsaid connector member extending through a passage formed at least inpart by said housing mean; and adjusting means for urging said movablebearing seat member toward said ball member such that the inner bearingsurfaces of said seat members engage the outer bearing surface of saidball member, said adjusting means comprising cap means arranged to closethe open end of said bearing chamber, and screw means having threads forengaging a threaded opening in said cap means and an inner end arrangedto apply pressure to a pressure surface of said movable bearing seatmember in response to rotation of said screw means while in saidthreaded engagement with said cap means, said pressure surface being ona side of said movable bearing seat member opposite from said ballmember, and said movable bearing seat member being arranged to be forcedagainst said ball member by said pressure, the amount of said pressurebeing adjustable by said rotation of the screw means.
 14. Aself-adjusting bearing assembly, comprising:a ball member fixed to aconnector member, said ball member having an outer bearing surfaceextending about at least a central portion of the ball member; a housingdefining a bearing chamber having an open end; two opposing bearing seatmembers arranged in said bearing chamber to define therebetween a spacefor receiving said ball member, each of said bearing seat members havingan inner bearing surface conforming substantially to the shape of theouter bearing surface of said ball member and arranged to engage theouter bearing surface of said ball member while allowing said ballmember to rotate, at least one of said bearing seat members beingmovable in said bearing chamber, and said connector member extendingthrough a passage formed at least in part by said housing; a resilientdiaphram arranged to cover and seal the open end of said bearingchamber; a pressure chamber in fluid communication with a first surfaceof said diaphram; and, a fitting in fluid communication with saidpressure chamber and comprising a valve for pressurizing said pressurechamber with a pressurized fluid, a second surface of said diaphramopposite to said first surface being arranged to apply pressure to apressure surface of said movable bearing seat member in response to saidchamber pressure, said pressure surface being on a side of said movablebearing seat member opposite from said ball member, and said at leastone movable bearing seat member being arranged to be urged toward saidball member by said diaphram such that the inner bearing surfaces ofsaid seat members engage the outer bearing surface of said ball memberin response to said chamber pressure.
 15. A self-adjusting bearingassembly according to claim 14, wherein said pressure chamber isprovided by a closure cap arranged on said housing adjacent to the openend of said bearing chamber, wherein said fitting is received in aninlet passage formed in said closure cap, and said valve is a checkvalve permitting said fluid to be introduced into said pressure chamberwhile preventing said introduced fluid from escaping from said pressurechamber through said inlet passage.
 16. A self-adjusting bearingassembly according to claim 15, wherein a peripheral portion of saidclosure cap is secured to an end portion of said housing member, andwherein a rib extending around a peripheral portion of said diaphram isheld in sealing engagement with a groove in said housing end portion bysaid closure cap peripheral portion.
 17. A self-adjusting bearingassembly according to claim 14 further comprising a second fitting forpermitting said fluid to be introduced from said pressure chamberthrough said movable bearing seat member into an interface between theinner bearing surface of said movable bearing seat member and the outerbearing surface of said ball member when said chamber pressure isgreater than a predetermined value.
 18. A self-adjusting bearingassembly according to claim 17, wherein said fluid is a lubricatingsubstance and a groove is formed in a portion of the inner bearingsurface of said movable bearing seat member, wherein said second fittingis received in a passage formed in said movable bearing seat member,wherein the groove in said movable member bearing surface is in fluidcommunication with said movable member passage, and wherein said grooveprovides a channel for distributing said lubricating substance betweensaid outer bearing surface of the ball member and said inner bearingsurfaces of the bearing seat members.
 19. A self-adjusting bearingassembly according to claim 14, wherein the other of said bearing seatmembers is fixed in position within said housing, and said movablebearing seat member is slidable within the bearing chamber of saidhousing in a movement direction; wherein the inner bearing surface ofsaid movable bearing seat member is adjacent said ball member on a sideof said ball member substantially opposite the inner bearing surface ofsaid fixed bearing seat member; and wherein said movable and fixedbearing seat members are separated by a slot, said slot extendingtransversely to said movement direction to provide a space between saidbearing seat members to allow said movable bearing seat member to movetoward said fixed bearing seat member in response to said chamberpressure and the wearing of said bearing surfaces.
 20. A self-adjustingbearing assembly according to claim 14, wherein said housing is providedby an end portion of a tie rod component of a vehicle steering assembly,and said connector member extends through an opening formed in asidewall of said tie rod end portion; wherein said movable bearing seatmember is arranged to move in a direction of an axis of said bearingchamber; wherein said bearing chamber axis is substantiallyperpendicular to a longitudinal axis of said tie rod component; andwherein said connector member includes a connector element forconnecting a distal end portion thereof to another component of saidsteering assembly.
 21. A self-adjusting bearing assembly,comprising:bearing means comprising a ball member and a connectormember, said ball member having an outer bearing surface extending aboutat least a central portion of the ball member; housing means defining abearing chamber having an open end; bearing seat means comprising atleast two opposing seat members arranged in said bearing chamber todefine therebetween a space for receiving said ball chamber, each ofsaid seat members having in inner bearing surface conformingsubstantially to the shape of the outer bearing surface of said ballmember and arranged to engage the outer bearing surface of said ballmember while allowing said ball member to rotate, at least one of saidseat members being movable in said bearing seat chamber, and saidconnector member extending through a passage formed at least in part bysaid housing means; and adjusting means for urging said movable seatmember toward said ball member such that the inner bearing surfaces ofsaid seat members engage the outer bearing surface of said ball member,said adjusting means comprising cap means arranged to close the open endof said bearing chamber, a resilient diaphragm cooperating with said capmeans and said movable seat member to provide a pressure chamber forapplying a biasing force to a pressure surface of said movable seatmember in response to fluid pressure in said pressure chamber, and meansfor pressurizing said pressure chamber with a fluid, said pressuresurface being on a side of said movable seat member opposite from saidball member, and said movable seat member being arranged to be forcedagainst said ball member by said biasing force.
 22. A self-adjustingbearing assembly according to claim 21 wherein said adjusting meansfurther comprises screw means having threads for engaging a threadedopening in said cap means and an inner end arranged to exert amechanical force on the pressure surface of said movable seat member inresponse to rotation of said screw means while in said threadedengagement with said cap means, said mechanical force causing saidmovable bearing seat member to be forced against said ball member andthe amount of said mechanical force being adjustable by said rotation ofthe screw means.
 23. A self-adjusting bearing assembly according toclaim 21 wherein said resilient diaphragm cooperates with said cap meansto close and seal the open end of said bearing chamber.
 24. Aself-adjusting bearing assembly according to claim 23 wherein saidpressure chamber is in fluid communication with a first surface of saiddiaphragm, and a second surface of said diaphragm opposite to said firstsurface is arranged to apply said biasing force to the pressure surfaceof said movable seat member in response to said chamber pressure.
 25. Aself-adjusting bearing assembly according to claim 21 wherein:saidhousing means is provided by an end portion of an elongated component,said connector member extends through an opening formed in a sidewall ofsaid elongated component, said movable seat member is arranged to movein a direction of an axis of said bearing chamber, and said bearingchamber axis is substantially perpendicular to a longitudinal axis ofsaid elongated component.